seq_linter should catch seq(length()), redirecting to seq_along()

[MichaelChirico]

seq(0)
# [1] 1 0

i.e., seq(length(x)) is subject to the same unexpected/error-prone edge-case behavior as other usages caught by seq_linter()

[IndrajeetPatil]

I think this already works? We just need to add tests for this scenario.

library(lintr)

lint(
  text = "1:seq(length(x))",
  linters = seq_linter()
)
#> <text>:1:1: warning: [seq_linter] 1:seq(...) is likely to be wrong in the empty edge case. Use seq_len() instead.
#> 1:seq(length(x))
#> ^~~~~~~~~~~~~~~~

^{Created on 2022-07-24 by the reprex package (v2.0.1)}

[IndrajeetPatil]

It does produce a false positive though:

library(lintr)

lint(
  text = "1:seq_len(length(x))",
  linters = seq_linter()
)
#> <text>:1:1: warning: [seq_linter] 1:seq_len(...) is likely to be wrong in the empty edge case. Use seq_len() instead.
#> 1:seq_len(length(x))
#> ^~~~~~~~~~~~~~~~~~~~

^{Created on 2022-07-24 by the reprex package (v2.0.1)}

[MichaelChirico]

NB: there's no '1:' in my example

…

On Sat, Jul 23, 2022, 11:40 PM Indrajeet Patil ***@***.***> wrote: It does produce a false positive though: library(lintr) lint( text = "1:seq_len(length(x))", linters = seq_linter() )#> <text>:1:1: warning: [seq_linter] 1:seq_len(...) is likely to be wrong in the empty edge case. Use seq_len() instead.#> 1:seq_len(length(x))#> ^~~~~~~~~~~~~~~~~~~~ Created on 2022-07-24 by the reprex package <https://reprex.tidyverse.org> (v2.0.1) — Reply to this email directly, view it on GitHub <#1467 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AB2BA5KW5WXRDBYUT4UTSC3VVTQNRANCNFSM54PBHE4Q> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[IndrajeetPatil]

Oops! Gotcha. This indeed doesn't produce a lint:

library(lintr)

lint(
  text = "seq(length(mtcars))",
  linters = seq_linter()
)

^{Created on 2022-07-24 by the reprex package (v2.0.1)}

[IndrajeetPatil]

Is this better?

With #1468:

library(lintr)

lint(
  text = "seq(length(mtcars))",
  linters = seq_linter()
)
#> <text>:1:1: warning: [seq_linter] seq(length(...)) is likely to be wrong in the empty edge case. Use seq_along(...) instead.
#> seq(length(mtcars))
#> ^~~~~~~~~~~~~~~~~~~

lint(
  text = "seq(nrow(mtcars))",
  linters = seq_linter()
)
#> <text>:1:1: warning: [seq_linter] seq(nrow(...)) is likely to be wrong in the empty edge case. Use seq_len(...) instead.
#> seq(nrow(mtcars))
#> ^~~~~~~~~~~~~~~~~

^{Created on 2022-07-24 by the reprex package (v2.0.1)}